1. Field of the Invention
The present invention relates to a head suspension for a disk drive incorporated in an information processing apparatus such as a personal computer.
2. Description of the Related Art
A hard disk drive (HDD) records and reproduces information to and from rotating magnetic or magneto-optical disks. The HDD has a carriage driven by a positioning motor, to turn around a spindle.
An example of the carriage is disclosed in U.S. Pat. No. 4,167,765. The carriage of this disclosure includes carriage arms, a head suspension attached to a front end of each carriage arm, a head attached to the head suspension, and a slider attached to the head. When disks in a disk drive where the carriage is arranged are rotated at high speed, the sliders slightly float from the disks, and air bearings are formed between the disks and the sliders.
FIG. 27 is a sectional view showing a part of a disk drive with head suspensions according to a prior art. The disk drive 101 has a carriage 105. The carriage 105 is driven by a positioning motor 107 such as a voice coil motor, to turn around a spindle 103. The carriage 105 has a plurality of (four in FIG. 27) carriage arms 109 each having at least one head suspension 111 with a head 113 arranged at a front end thereof.
The carriage 105 is turned around the spindle 103, to move each head 113 onto a target track on a disk 115. The head 113 has a slider 117 facing the track on the disk 115, a transducer (not shown) held by the slider 117, and the like.
When the disks 115 are rotated at high speed, air enters between the disks 115 and the sliders 117 and forms air bearings at there to slightly float the sliders 117 from the disks 115.
FIG. 28 shows an example of the head suspension 111. The head suspension  111 includes a load beam 119 made of a precision thin plate spring, a flexure 121 made of a very thin plate spring fixed to the load beam 119 by, for example, laser welding, and a base plate 123 fixed to a base part of the load beam 119 by, for example, laser welding. The base plate 123 is fixed to a head suspension fitting face of the carriage arm 109.
Recent hard disk drives employ high-density disks and drive the disks at high speed. Such high-density disks involve narrow tracks. Due to such narrow tracks and vibration such as butterfly-mode vibration on the head suspension 111 caused by, for example, air disturbance even at high frequencies, it is difficult to correctly maintain the head 113 on a track of a disk.
Many studies and improvements have been made for the carriage arms and head suspensions in connection with controlling amplitudes for various resonance modes, increasing resonance frequencies, and suppressing air disturbance.
According to the prior art of FIG. 28, the flexure 121 is fixed to the load beam 119, and therefore, the load beam 119 is directly affected by the weight of the flexure 121 including the slider 117, to decrease a resonance frequency. In addition, the movement and vibration of the flexure 121 due to the movement of the slider 117 are directly transmitted to the load beam 119, to deteriorate the vibration characteristics of the load beam 119.
These circumstances make it difficult to correctly control amplitudes and precisely position the head 113 on a track on a high-density, high-speed disk.